Fume exhausting apparatus, in particular for chimneys and fireplaces

Abstract: A fume-exhausting apparatus in particular for chimneys and fireplaces comprises a plurality of fume-conveying channels (5, 105) extending whithin a hood (3, 103) in a chimney or fireplace and exhibiting lower openings (5a) directed downwardly and disposed close to the lower inlet mouth (3a) of the hood (3, 103) and upper openings (5b) directed upwardly, close to the lower end of the flue (4). In an alternative version, the apparatus comprises at least one main section (102) for recovering heat from the fumes, consisting of a heat-exchange chamber (106) adapted to hold a circulating fluid to be heated, and a plurality of main pipe coils (105) extending within the heat-exchange chamber (106) and adapted to receive and convey the fumes coming from the hood (103).

Description: The present invention relates to a fume-exhausting apparatus, in particular for chimneys and fireplaces, having the features recited in the preamble of claim 1. It is known that chimneys, fireplaces and similar structures do not always have a satisfactory and appropriate draught, that is a capacity of appropriately conveying and drawing fumes into a flue. In fact, sometimes fume vortices and refluxes towards the room where a fireplace is located may be created, due either to the presence of excess smoke in the hearth, for example when some foods are being barbecued, or to an imperfect design and construction of the fireplaces themselves. Under the foregoing and other similar situations, for example when particular weather conditions are present or, above all, at the initial ignition step, when the operating temperatures of the flue do not correspond to those provided for a steady state operation, fumes do not succeed in overcoming the upper hood restriction at the point where said hood is connected to the flue and therefore tend to invade the inner environment or room in which the chimney or fireplace is located. The document FR-A-2 467 358, which is herein referred as the most relevant state of the art, teaches to provide, in a chimney comprising a hearth and a hood for collecting fumes to be sent to a flue, a number of channels having lower openings directed downwardly close to the lower inlet mouth of the hood and upper openings directed upwardly and communicating with the lower end of the flue. An air stream is drived around the conveying channel and blown into the room, in such a manner to provide a heat recovering from the fumes. US Patent n. 4,100,913 teaches to provide conveying channels extending from the upper portion of the hood and entering the lower end of the flue. Also in this document the conveying channels are arranged for providing a heat recovering by an air stream passing around the channels itselves. Also US Patent n. 2,277,381 teaches to provide conveying channels extending from the upper portion of the hood and arranged for providing a heat recovering from the fumes, by an air stream blown around the channels itselves. Under this situation the technical task underlying the present invention is to provide a fume-exhausting apparatus, in particular for chimneys and fireplaces, capable of substantially eliminating the above drawbacks. Within the scope of this technical task it is an important object of the present invention to devise a fume-exhausting apparatus capable of enabling the natural draught of a chimney or fireplace to be increased to an important amount without resorting to the use of fans or similar power-driven exhausting devices, so that under any circumstances all smoke emissions into the room where the chimney or fireplace is located can be avoided. The technical task mentioned and the object specified are substantially achieved by a fume-exhausting apparatus, in particular for chimneys and fireplaces, which is characterized in that it comprises the features recited in the characterizing portion of claim 1. The description of some preferred embodiments of a fume-exhausting apparatus according to the invention is given hereinafter by way of non-limiting example, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of one embodiment of the apparatus fitted in a chimney; Fig. 2 is a side view partly in section of a second embodiment of the apparatus having the features of the claimed fume-exhausting apparatus; Fig. 3 is a side view partly in section of another embodiment of the apparatus; Fig. 4 is a perspective and partly cut-away view of the apparatus shown in Fig. 3; Referring to the drawings, the fume-exhausting apparatus according to the invention has been generally identified by reference numeral 1. The apparatus 1 is adapted to be fitted in a chimney or fireplace of a conventional type known per se comprising a hearth 2, a hood 3 for collecting the fumes produced on the heart, and a flue 4. It comprises a plurality of channels 5 for conveying fumes, located above the hearth 2 and therefore extending within the hood 3. The conveying channels 5 exhibit lower openings 5a directed downwardly, disposed close to the lower inlet mouth 3a of the hood 3, and upper openings 5b directed upwardly and disposed close to a lower end 4a of the flue 4, so that they are affected by a draught effect created thereinto. As a whole, the transverse section of the conveying channels 5 has an area corresponding at least to the area of the transverse section of the flue and preferably greater than the latter by 50%. In one embodiment shown in Fig. 1, the conveying channels 5, for example defined by lengths of rectilinear pipes having a circular section, are disposed in mutual side by side relation to form a bundle and converge close to the upper portion 3b of the hood 3, so that they substantially occupy, at least close to the upper openings thereof 5b, the whole transverse section of the hood 3, apart from the gaps present between the pipes as a result of their circular section. In this embodiment preferably one main conveying channel or pipe 5c is provided which is disposed centrally substantially above the flame present in the hearth 2, as well as a plurality of auxiliary conveying channels or pipes 5d disposed perimetrically and each of them having a transverse section the area of which is lower than that of the trasverse section of the main pipe 5c. In the progress of experimental tests the results of which are herein reproduced by way of description only, an excellent draught for a flue of a 25x25 cm square section has been offered by combining together a main pipe with a diameter of 14 cm and nine auxiliary pipes each with a diameter of 10 cm, disposed in groups of three pipes each, in front and laterally of the hearth. The hearth sizes substantially were 70 cm in width, 50 cm in depth and 56 cm in height. In a 22x22 cm flue use has been made of a main pipe with a diameter of 14 cm and seven auxiliary pipes with a diameter of 10 cm disposed so as to form one three-piece row at the front and two two-piece rows laterally, for a hearth being 50 cm wide, 40 cm deep and 45 cm high. Excellent results have been achieved as well by the use of nine auxiliary pipes with a diameter of 8 cm, instead of seven auxiliary pipes with a diameter of 10 cm. Still in accordance with the present invention, provision may be also made for at least one lower plate-like closing element 6a extending close to the lower inlet mouth 3a of the hood 3, exhibiting a perimetric edge shaped such as to mate the inner sizes of the hood 3 and provided with through holes sealingly engaging the respective lower end portions of the conveying channels 5. In the presence of this lower plate-like closing element 6a, all fumes produced in the hearth 3 are forced to go up to the flue 4 exclusively through the conveying channels 5. If one intends to recover at least part of the fume heat in order to generate hot air, in addition to the lower plate-like closing element 6a an upper plate-like closing element 6b is also provided which is disposed close to the upper portion 3b of the hood 7. The upper plate-like element 6b is also provided with through holes adapted to sealingly engage the upper end portions of the conveying channels 5 and also has a perimetric shaped edge the shape of which is adapted to mate the inner sizes of the hood 3. In this manner the lower and upper plate-like closing elements, 6a and 6b, substantially define, in cooperation with the hood 3, a heat-exchange sealed chamber with respect to the fumes, crossed by the conveying channels 5 themselves. Suitable air intakes 7 formed in the hood 3 for admitting cold air from the surrounding atmosphere and emitting hot air thereinto (only one admission intake being shown in Fig. 1) enable a forced air circulation to be created, optionally with the aid of ventilation means, which air passing through the gaps present between the conveying channels 5 can be heated by the heat transmitted from the fumes. In a further embodiment shown in Figs. 3 and 4, the conveying channels 5 are disposed in mutual side by side relation and in alignment with each other and they occupy the hood volume, and therefore the transverse hood section, only partially. The conveying channels 5 in this embodiment exhibit their lower openings 5a disposed in alignment along the front side of the lower inlet mouth 3a of the hood 3, so as to define a suction area extending along the whole extension of said side. Preferentially the conveying channels 5 are integral with each other and consist of a unitary body 8, being divided by partitions 8a. Such unitary body 8 can be easily engaged within an already installed hood in order to improve performance of same in drawing fumes. The upper openings 5b of the conveying channels 5 defined by the partitions 8a open into an interconnecting pipeline 9 at differentiated heights in order not to hinder the respective smoke flows. Preferentially, as shown in Fig. 4, the upper ends 5b of the conveying channels 5 located at the laterally opposite ends of the unitary body 8 communicate with the upper portion of the interconnecting pipeline 9 by two tubular headers 20 exhibiting end portions 20a adapted to be laterally fitted in the interconnecting pipeline as they bend according to the progress direction of the fumes along said pipeline. Advantageously, connected in succession to the interconnecting pipeline 9 is a draught duct 10 having an extension enabling one upper end thereof 10a to be directly located in the flue 4. In this manner, close to the upper end 10a there is negative pressure created by the quick flowing of the fumes from the hood 3, which negative pressure greatly increases the suction effect of the conveying channels 5. Finally, in order to be sure that even under a situation of maximum smoke production any smoke admission into the room is prevented, each conveying channel 5, according to the invention, is divided, as shown in Fig. 2, into a lower movable portion "A" and an upper fixed portion "B", capable of telescopically sliding into each other. Suitable support and movement means for the lower portions enable said portions to be positioned at variable heights above the hearth and in particular by virtue of said means the lower openings 5a of the conveying channels 5 can be lowered directly close to the fume production region. Said supporting and movement means are not shown as they can he made in any known manner. One embodiment of the same is suggested in an Italian patent application filed on same date in the name of the same applicant. As shown in Fig 2, an auxiliary conveying hood 11 may be associated with the lower portions "A" of the conveying channels 5, at the lower ends 5a thereof. Operation of a fume-exhausting apparatus, in particular for chimneys and fireplaces, described above mainly as regards structure, is as follows. The conveying channels 5 enable the whole fume flow to be divided into partial flows, each of which exhibits a reduced vorticity and greater upward kinetic energy. Practically, the apparatus in question enables the so-called draught effect created within the flue to be moved much closer to the flame or, in other words, to the real fume-producing area, thereby enabling said fumes to be drawn upwardly in a stronger manner. In the traditional prior art solutions the results of said draught effect have been practically zero at distances ranging between 20 and 30 cm from the lower end of the flue itself. In particular, in the third embodiment shown in Figs. 3 and 4 a suction area extending along the front edge of the hearth is created so as to form a barrier against the emission of fumes towards the room where the fireplace is located. It is pointed out that the last-mentioned embodiment of the apparatus makes it possible to intervene on already installed fireplaces with ease, because the apparatus can be readily fitted into a hood and engaged to the front wall thereof. Therefore the apparatus of the invention is capable of making a fireplace flue work properly even if it has an inefficient draught as a result of an imperfect design and/or construction, or at all events is capable of improving performace of a fireplace even under the most unfavourable circumstances.

Claims: A fume-exhausting apparatus, in particular for chimneys and fireplaces, said apparatus comprising a hearth (2) and a hood (3) for collecting said fumes to be sent to a flue (4), said apparatus comprising a plurality of channels (5) for conveying said fumes, which conveying channels (5) have lower openings (5a) directed downwardly close to the lower inlet mouth of said hood (3), and upper openings (5b) directed upwardly and communicating with the lower end of the flue, characterized in that said conveying channels (5) are each comprised of at least one lower movable portion ("A") and one upper fixed portion ("B") telescopically sliding into each other, and in that support and movement means for said movable lower portions are provided for positioning them at a desired height above said hearth (2). An apparatus according to claim 1, characterized in that said conveying channels (5) are defined by lengths of rectilinear pipes disposed in mutual side by side relation and converging close to an upper portion of said hood (3). An apparatus according to claim 1, characterized in that said conveying channels (5) comprise a main conveying channel (5c) disposed centrally substantially above the flame in said hearth (2) and a plurality of auxiliary conveying channels (5d) disposed perimetrically and each of them having a transverse section the area of which is lower than that of a transverse section of the main conveying channel (5c). An apparatus according to claim 1, characterized in that said conveying channels (5) all together exhibit a transverse section the area of which corresponds at least to the area of the transverse section of said flue (4). An apparatus according to claim 1, characterized in that provision is made for at least one lower plate-like closing element (6a) extending close to said lower inlet mouth (3a) of the hood (3) and exhibiting through holes adapted to engage the lower end portions of said conveying channels (5). An apparatus according to claim 5, characterized in that it further comprises an upper plate-like closing element (6b) disposed close to an upper portion (3b) of said hood (3) and exhibiting through holes adapted to engage the upper end portions of said conveying channels (5), said lower (6a) and upper (6b) plate-like closing elements defining, in cooperation with said hood (3), a chamber for producing hot air. An apparatus according to claim 1, characterized in that said conveying channels (5) occupy the volume of said hood (3) partially and exhibit their respective lower openings (5a) consecutively aligned along the front side of the lower inlet mouth (3a) of said hood (3). An apparatus according to claim 7, characterized in that said conveying channels (5) are aligned and in side-by-side relation and integrally embodied by a unitary body (8) capable of being engaged to an already installed hood (3). An apparatus according to claim 8, characterized in that said unitary body (8) comprises an interconnecting pipeline (9) into which said upper openings (5b) of said conveying channels (5) open, at heights differentiated from each other. An apparatus according to claim 9, characterized in that a draught duct (10) having its upper end (10a) disposed in said flue (4) is connected in succession to said interconnecting pipeline. An apparatus according to claim 1, characterized in that it further comprises an auxiliary hood (11) connected to the lower ends (5a) of said lower movable portions ("A") of the conveying channels (5).

Inventors: DELLA ROCCA GIANFRANCO, DELLA ROCCA GIANLUCA, DELLA ROCCA, GIANFRANCO, DELLA ROCCA, GIANLUCA
Applicants: DELLA ROCCA GIANFRANCO, DELLA ROCCA GIANLUCA, DELLA ROCCA, GIANFRANCO, DELLA ROCCA, GIANLUCA
Application year: 1994
Main classification: F24B1
IPC codes: F24B1